Dovetail Tool - Questions?

Dan Mosley

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Palm Springs, Ca
I bought some supplies awhile back and they had a sale on some tools so I picked up this Dovetail tool with my purchase. It has been sitting around and I have never used it as I usually make my own dovetails with my Ci1. Even then its few and far between because I usually make a flat bottom to my vessels and bowls with a slight concave in them.

Of the times I have made a dovetail bottom I had a heck of a time getting rid of the black that the jaws put on the wood from the holding in expansion mode. Some say it comes off easy with Lemon juice but I have not tried it. I am going to make a few large turnings soon and thought I would make a dovetail bottom on them but I need a better understanding of the use of the tool.

Questions:
1) - How do you sharpen the tool ? looks a bit complicated compared to the normal turning tools

2) - Do you have to go in as deep as the shoulder of the tool ? It seems it would be a awful deep dovetail

3) - I was told that you do not have to tigthen it up very hard but to just make sure it is snugged up good to avoid spliting the bottom. Sound right ?
Anybody else experience the black marks from the jaws I mentioned ?
 

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I've only done one or two pieces with a recessed hold, so I'll let others answer your questions about how deep to make it. (Although I'm pretty sure you don't go the full depth of the tool.) I'm pretty sure it's sharpened like any other scraper...just this one has two faces. There's no need to grind all the way into the corner, assuming you don't cut to the full depth of the tool. It's just the first 1/4" or so that's going to be doing the cutting.

As far as the black marks, that will vary, depending on A) how wet the wood is, B) the amount of tannins in the wood (oak and mesquite have a lot, for example), and C) how long the piece is in the jaws. I've had wet mesquite stain deeper than I wanted to turn out, but I blame it on leaving the piece in the chuck for a day or two.
 
Vaughn, Dan, I wonder if tape (maybe masking tape?) might be used around the inside of the dovetail so the metal of the jaws wouldn't make direct contact with the wood, maybe helping to avoid those tanin stains? I wonder? :dunno::huh:
 
Yeah I agree the cut would not be to the depth of the tool. I saw on a video somewhere where the guy put some blue painters tape (not that the color matters) on the outside of chuck jaws and used it so, I assume it would not slip and im sure he was using it to avoid the black marks.
 
I’m not an expert by any means so take what I say with a shaker of salt.
For the depth I base it upon the wood and the overall size. For a softer wood I go deeper as well as with larger 10”+ items. In general between 1/8 and 3/8" deep.
I made my own tool because of the little use they receive. Usually you are only cutting a width on 0-1/8” (top of the dovetail will be cut 0 and the bottom the 1/8”. I make my initial cuts with a parting tool until my dovetail will fit in. Then it is only a sideways scrape to about 1/8”.
After using mine a short time I reground the “recess” cutter side to a 45-degree delivery.
The live center was a pain to work around, especially with the 50mm jaws. Now, with the recess cut with a parting tool, I hold the tool at a 45-degree angle to the tool rest. The live center does not get in the way and all I have to do is pull it to me to cut the dovetail.
That probably makes no sense.

I have never had black marks from using mine. If the marks are from the jaws, how do you remove the black marks from the jaws when used in spigot mode? It’s the same steel against the same wood?

Snug it up good and just like with a spigot, recheck and retighten after a few minutes if the wood is green.

You can still make a flat bottom with a slight concave, that is what I normally do also.
Just allow in your design for the area to be cut away. This will have to be at the end when you have reversed in a compression/friction/donut/or other chucking method to clean up the base.

Here is a picture of my convoluted dovetail tool. I just ground it and used a diamond stone on the top surface. Works fine.
 

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Dan as far as sharpening I made one of those tools out of a BB square scraper. I adjusted my platform on the wolverine to match the bevel or front of the scraper and sharpen the front. I then move the tip of the handle to the left and sharpen the side grind the same as the front. You have to sharpen it though with a slight angle for the dovetail. Has worked well for me for over 2 yrs since I made it. Since you already have it shaped I would match the front set my platform and go. Turn it and sharpen the side the same angle. Saves a lot of messing around time.

As far as the dovetail goes I to between a 1/8" to no more than 3/8". I snug it down pretty good but not tight enough to tear or crack the wood. I don't worry about the black because I clean that up when I do the bottom when mounted in my vacuum chuck or donut chuck.
 
Mike - Bernie...................Lemon juice will also take off the black marks from what someone else told me. Clean the jaws well before starting, and place some masking tape on the jaws could work to. I have not tried any of them because like you said when reversed it is just as easy I guess to clean up. Today I made 5 bowls with a dovetail bottom and figured that as long as i do not make the bottom area when you transition up to thin - you only really have to snug it down (meaning you do not need to over tighten).
In the past I have broke them by tightening up to tight but learned quick that its really in how you make the bottom to transition that will help in not having that issue................

I do not own a vac chuck so im thinking ill just use my donut chuck to true up the bottom and finish sand it......or with a nub still on I suppose I could jam chuck it - finish the bottom - grind off and sand were the nub was.

Ill post pictures when I can......starting to lose alot of wood so I have been spending what time I have to rough out, seal and store as many as I can. Wheather here is starting to turn I guess................LOL
 
Mike.............I am not following you so good on how you do your dovetails.
I find that using the powergrip jaws on my supernova I can fairly easily make the dovetail. However, with the smaller spigot jaws I am not able to work around the tailstock in order to create a smaller dovetail. Whether I use a parting tool or a dovetail tool would not matter because there is still lack of working area to create it........................
Am i missing something in what your saying to create a smaller dovetail ??

Thanks
 
Hi Dan,
First I have the Nova live center and Nova chucks (other live centers and chuck jaws will be different).
Using the 50mm jaws I can get my parting tool in to make the initial depth cut even though it is tight and the tool is angled down more than I like. The problem was getting a dovetail tool in.
For the tool I just used a old 1” chisel. The left side was ground 45 degrees from the center on the end. Then I formed the 15 degree right hand side for spigots/tenons, and on the left hand side a 15 degree from the new 45 degree face for expansion.
“A” and “B” are now the bottom of the recess depending on how the tool is presented to the wood and are used to true up the bottom if not flat from the parting tool.

With the Nova standard 50mm jaws, Teknatool says to NOT CUT A DOVETAIL when mounting on a tenon/spidot, only when mounting in an expansion method. My tool is made to reach into the opening made by the parting tool to form the dovetail in expansion mode.

This is different from the PowerGrip jaws which I also have. You cut a dovetail for expansion with these and also what they call dovetail compression (a short spigot/tenon). For a long spigot/tenon (about ¾” or more?) you do not cut a dovetail for compression.

This probably made it worse but maybe not.
 

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One of my Skews was sharpened to the angle to match my scrolling chuck, when turning a spigot
on the bottom of a bowl and being held on the outside of the spigot.

Dave
 
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